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Natural Resources

Learn about groundwater conservation methods, terminology, movement, storage, and problems in Southern California, including issues like contamination and seawater intrusion.

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Natural Resources

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  1. Natural Resources Water

  2. Water Conservation • Water is saved for Public Use • Done in mountain and upper valley reservoirs and lower valley drainages • Water may be directed to spreading grounds • Recharges groundwater supplies

  3. Water Conservation • Importance of this Function • Groundwater is cheaper than imported water • Groundwater is not subject to Earthquake emergency problems

  4. What is Groundwater? • Water found in the pores and fractures of soil and bedrock • Largest reservoir of fresh water • Tends to be less polluted than surface water

  5. Groundwater Terminology • Belt of soil moisture • Zone of saturation • Zone of aeration • Capillary fringe • Water table

  6. Groundwater Terminology • Water table • The upper limit of the zone of saturation • Depth is highly variable • Varies seasonably and from year to year • Shape is usually a subdued replica of the surface topography

  7. Groundwater Movement & Storage • Porosity • Percentage of total volume of rock or sediment that consists of pore spaces • Permeability • The ability of a material to transmit a fluid

  8. Groundwater Movement & Storage • Specific retention • The portion whish is retained as a film on particles, rock surfaces, and pore spaces • Specific yield • The portion which will drain under gravity • In general, • Porosity = Specific retention + Specific yield

  9. Groundwater Movement & Storage • Aquifer • A zone of Earth material capable of supplying groundwater at a useful rate from a well • Aquitard • A zone of Earth material that holds water but cannot transmit it fast enough to pump from a well

  10. Getting Groundwater Out of the Ground • “Natural” Methods • Springs, Hot Springs, & Geysers

  11. Getting Groundwater Out of the Ground • Man-made Methods • Wells

  12. Problems • Non-renewable resource / Groundwater Recharge • Can take centuries to occur • Hindrances: • Paved river channels • Urbanization

  13. Ecological Damage

  14. Problems • Subsidence • Over pumping of groundwater • Water removed from pore spaces • Air filled pores collapse • Grains pack together more tightly • Ground subsides

  15. Problems • Sources of Contamination • Natural Sources • Seawater Intrusion • Biologic activity / organisms • Bacteria and viruses • Naturally occurring elements • Uranium, radium, arsenic, and fluoride

  16. Seawater Intrusion

  17. Problems • Sources of Contamination • Human Caused • Acid Rain • Agricultural / Industrial Run-off • Leakage from waste disposal, treatment, or storage sites. • Discharges from factories, industrial sites, or sewage treatment facilities. • Leaching from pesticides and fertilizers on yards or fields. • Accidental chemical spills. • Leakage from underground storage tanks. • Improper disposal of household wastes such as cleaning fluids, paint, and motor oil

  18. The movement of toxic materials in the environment Source

  19. Groundwater In Southern California • Geological Setting • S. California is broken into fault blocks of different elevation • Sediment deposited on the lower blocks forms the aquifers

  20. Groundwater In Southern California • Coastal Plain • These areas are formed by alluvial deposits of the LA, San Gabriel, and Santa Ana Rivers • Unconfined aquifers lie just beyond the narrows

  21. Los Angeles County, California Hydrologic Unit Code 18070106 Latitude  34°05'35", Longitude 117°57'35" NAD27 Gage datum 387 feet above sea level NGVD29 The depth of the well is 196.2 feet below land surface. The depth of the hole is 200 feet below land surface.

  22. Groundwater In Southern California • Inland Valleys • Water here drains in the subsurface through the narrows to the coastal plain • San Fernando Valley • Has extensively used groundwater for agriculture and domestic needs • Now polluted with TCE - a Superfund site • Has also used Owens Valley water since 1915

  23. Groundwater In Southern California • Inland Valleys • San Gabriel Valley • Groundwater is heavily used • Basin has the storage capacity of 10 million acre feet • The San Gabriel Basin is polluted with cancer causing chemicals • trichloroethylene (TCE) • perchloroethylene (PCE) • carbon tetrachloride (CTC)

  24. Groundwater In Southern California • San Gabriel Valley (continued) • San Gabriel Valley became a Superfund site in 1985 • More than 1 million people rely on the San Gabriel aquifer for drinking water.

  25. Sea Water Intrusion • This is a worldwide problem • First recognized here at Redondo Beach in 1912 • LA County Department of Public Works is responsible for prevention

  26. Sea Water Intrusion • The Barrier Projects • West Coast Basin Barrier Project • 10 miles from El Segundo to Palos Verdes • Dominguez Gap Barrier • 6 miles from San Pedro to Long Beach • Alamitos Barrier Project • 7 miles from Long Beach to Seal Beach

  27. Methods Of Augmenting Local Water Supplies • Water Importation by Aqueducts • Water Reclamation • Desalination • Icebergs

  28. History Of Aqueducts In California

  29. Methods Of Augmenting Local Water Supplies • Owens Valley Aqueduct • Colorado River Aqueduct • California Aqueduct

  30. Methods Of Augmenting Local Water Supplies • Owens Valley Aqueduct • Concept resulted from the drought of 1892-1904 which threatened the growth of LA • Conceived by Fred Eatonand William Mulholland • US Reclamation Serviceinterested in area for irrigation purposes J.B. Lippincott, Fred Eaton and William Mulholland. This photograph appeared in the Los Angeles Times, August 6, 1906.

  31. Methods Of Augmenting Local Water Supplies • Owens Valley Aqueduct • Opposition to the aqueduct • Began in Owens Valley with the first land acquisitions in 1905 • Still controversial today

  32. Methods Of Augmenting Local Water Supplies • Colorado River Aqueduct • Droughts from the mid-1920's to early 1930's resulted in 500,000 people of LA approving a $220 million bond issue in 1931 for a new aqueduct

  33. Methods Of Augmenting Local Water Supplies • Colorado River Aqueduct • The MWD (128 cities, 12 million people) built the Colorado River Aqueduct • Extends 242 miles from Lake Havasu behind Parker Dam • Supplied 1.2 million acre-ft/year to S. California for many years • Now reduced to 550,000 acre-ft/year • Supplies 6% of LA's needs • Supplies East LA, the Harbor & part of the central city

  34. Methods Of Augmenting Local Water Supplies • California Aqueduct • 2.5 million people of LA approved a $1.75 billion water project • Aqueduct stretches 444 miles from Oroville Dam • Deliveries began in 1971

  35. Methods Of Augmenting Local Water Supplies • Future Aqueducts are unlikely • Belief that more water means more people and more pollution • Water rationing first occurred in LA on July 1, 1977

  36. Methods Of Augmenting Local Water Supplies • Water Reclamation

  37. Methods Of Augmenting Local Water Supplies • Desalination

  38. Methods Of Augmenting Local Water Supplies • Icebergs

  39. ~ END ~

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